1. Filed of the Invention
This invention relates to an optical connector device for connecting optical fiber cords with each other in the field of optical communication between equipments in an OA (office automation) system, an FA (factory automation ) system, an automobile or the like.
2. Description of the Related Art
Examples of conventional optical connector devices for optically coupling optical fiber cords with each other includes the type, as disclosed in JP-A-9-222535, in which optical connectors each holding the optical fiber cord, are coupled with each other through a relay adapter.
More specifically, as shown in FIG. 5, each of the optical connectors 1 and 2 includes a pair of ferrule portions 1b, 2b which are provided at a connection side of a connector body 1a, 2a, molded of a resin or the like, and hold the optical fiber cords 3 inserted therein, respectively. Ferrule protection walls 1c, 2c of an approximately square tubular shape are formed, respectively, around the ferrule portions 1b, 2b in surrounding relation thereto in such a manner that a suitable clearance is formed between each ferrule protection wall and an outer peripheral surface of the corresponding ferrule portion. The ferrule portions 1b, 2b project from the ferrule protection walls 1c, 2c, respectively.
The ferrule protection walls 1c, 2c of each optical connector 1, 2 are interconnected by an interconnecting portion 1d, 2d, and guide projections 1e, 2e for fitting guide purposes with respect to fitting portions 5a provided at opposite end portions of the relay adapter 5, respectively, are formed, respectively, on the outer peripheral surfaces of the ferrule protection walls 1c, 2c. 
Retaining projections (not shown) detachably engaging with retaining holes 5b formed in the fitting portions 5a of the relay adapter 5 is formed on a lower surface of the interconnecting portion 1d, 2d. An elastic retaining portion if, 2f extends from a central portion of an upper portion of the connector body 1a, 2a into a space between the two ferrule protection walls 1c, 2c, and an upwardly-projecting retaining projection 1g, 2g is formed at a distal end of this elastic retaining portion 1f, 2f, and these retaining projections are detachably engaged with retaining holes 5c formed in the fitting portions 5a. 
An operating portion 1h, 2h is formed on a central portion of each elastic retaining portion 1f, 2f, and by depressing this operating portion 1h, 2h, the retaining engagement of the retaining projection 1g, 2g of the elastic retaining portion 1f, 2f with the retaining hole 5c in the relay adapter 5 can be canceled.
Ferrule fitting tubular portions 5d are provided at an intermediate portion of the interior of the relay adapter 5, and when the ferrule protection walls 1c, 2c of each optical connector 1, 2 are fitted into the corresponding fitting portion 5a, the ferrule portions 1b, 2b are fitted respectively into these ferrule fitting tubular portions, so that each of these ferrule fitting tubular portion intrudes into a space between the corresponding ferrule protection wall 1c, 2c and ferrule portion 1b, 2b. Screw fastening portions 5e are formed respectively on opposite (right and left) side surfaces of the relay adapter 5 at a central portion thereof.
When the ferrule protection walls 1c, 2c of each optical connector 1, 2 are fitted into the corresponding one of the fitting portions 5a formed respectively at the opposite end portions of the relay adapter 5, the ferrule portions 1b, 2b are fitted respectively into the ferrule fitting tubular portions 5d, and when the retaining projections 1g and 2g are brought into retaining engagement with the retaining holes 5c, respectively, end surfaces of the optical fiber cords 3 held respectively in the ferrule portions 1b of the optical connector 1 are joined and optically coupled respectively to end surfaces of the optical fiber cords 3 held respectively in the ferrule portions 2b of the optical connector 2.
In the above optical connector device according to the related construction, the ferrule portions 1b, 2b of each optical connector 1, 2 project from the ferrule protection walls 1c, 2c, respectively, and therefore there was a possibility that the distal ends of the ferrule portions 1b and 2b, subjected to an end processing, and the distal ends of the optical fiber cords 3 were accidentally contacted to undergo contact damage or damage due to contamination during the transport, the connecting/disconnecting operation or others.
With the above problem in view, it is an object of this invention to provide an optical connector device in which damage of ferrule portions and distal ends of optical fiber cords, held in these ferrule portions, due to contact or the like, is effectively prevented.
According to first technical means for solving the above problem, there is provided an optical connector device comprising:
a first optical connector having a ferrule portion holding an end portion of an optical fiber cord;
a second optical connector having a ferrule portion holding another optical fiber cord for being optically coupled to the optical fiber cord; and
a relay adapter for connecting the first optical connector and the second optical connector with each other,
wherein the optical fiber cord is optically coupled to the another optical fiber cord by connecting the first optical connector and the second optical connector with each other through the relay adapter;
the first optical connector includes a ferrule protection wall surrounding an outer peripheral surface of the ferrule portion of the first optical connector to have a space therebetween;
the ferrule portion of the first optical connector projects from the ferrule protection wall of the first optical connector;
the second optical connector includes a ferrule protection wall surrounding an outer peripheral surface of the ferrule portion of the second optical connector to have a space therebetween;
the ferrule protection wall of the second optical connector projects from the ferrule portion of the second connector;
the relay adapter has, at one end thereof, a fitting portion into which the ferrule protection wall of the first optical connector is fitted and a retained portion with which a retaining portion provided at the first optical connector is engaged in a withdrawal-preventing manner;
the relay adapter has, at the other end thereof, another fitting portion into which the ferrule protection wall of the second optical connector is fitted and another retained portion with which another retaining portion provided at the second optical connector is detachably engaged; and
the relay adapter has, at an intermediate portion of the interior thereof, a ferrule fitting tubular portion into which the ferrule portion of the first optical connector and the ferrule portion of the second optical connector are fitted in such a manner that the ferrule fitting tubular portion intrudes into a space between each of said ferrule protection walls and the corresponding ferrule portion.
According to second technical means for solving the above problem, there is provided an optical connector device comprising:
a first optical connector member having a ferrule portion holding an end portion of an optical fiber cord; and
a second optical connector member having a ferrule portion holding another optical fiber cord for being optically coupled to the optical fiber cord,
wherein the optical fiber cord is optically coupled to the another optical fiber cord by connecting the first optical connector member and the second optical connector member with each other;
the second optical connector member includes a ferrule protection wall surrounding an outer peripheral surface of the ferrule portion to have a space therebetween;
the ferrule protection wall of the second optical connector member projects from the ferrule portion of the second optical connector member; and
the first optical connector member comprises a first optical connector and a relay adapter;
a retaining portion provided at the first optical connector is engaged with a retained portion provided at the relay adapter in a withdrawal-preventing manner;
the first optical connector includes the ferrule portion of the first optical connector member and a ferrule protection wall surrounding an outer peripheral surface of the ferrule portion of the first optical connector member to have a space therebetween and is disposed the ferrule portion of the first optical connector member therein to project from the ferrule protection wall of the first optical connector; and
the relay adapter has, at one end thereof, a fitting portion into which the ferrule protection wall of the first optical connector is fitted and has, at the other end portion thereof, another fitting portion, into which the ferrule protection wall of the second optical connector member is fitted and a retained portion with which a retaining portion provided at the second optical connector member is detachably engaged and has, at an intermediate portion of the interior thereof, a ferrule fitting tubular portion into which the ferrule portion of the fitted first optical connector is fitted in such a manner that the ferrule fitting tubular portion intrudes into a space between the ferrule protection wall the first optical connector member and the ferrule portion of the first optical connector and into which the ferrule portion of the second optical connector member is fitted in such a manner that that ferrule fitting tubular portion intrudes into a space between the ferrule protection wall of the second optical connector member and the ferrule portion of the second optical connector member.